Hair waving with borohydrides



United StatesPatent O iCe HAIR WAVING WITH BOROHYDRIDES Herman Bogaty,Silver Spring, Md., and Alfred E. Brown, Washington, D. C., assignors toThe Gillette Company, Boston, Mass., a corporation of Delaware NDrawing. Application September 15, 1953, Serial No. 380,373

30 Claims. (Cl. 132-7) This invention relates to a method forpermanently waving human hair and to a composition therefor and pertainsmore specifically to the use of alkali metal borohydrides for thispurpose.

One object of the invention is to provide a hair-waving compositionwhich may be employed in the form of an aqueous solution or dispersionand which is free from sulfur and from undesirable odor.

Another object is to provide a hair-Waving composition which may beemployed in aqueous solution over a wide range of concentrations withoutserious change in the effect of the composition on the hair.

A further object is to provide a hair-waving composition which may beemployed in aqueous solution or dispersion over a wide range ofalkalinity with little danger of damaging the hair.

Still a further object is to provide a hair-waving composition Which maybe employed in aqueous solution or dispersion with little danger ofover-processing the hair regardless of wide variation in the time ofapplication of the composition to the hair.

Another object is to provide a method and composition for permanentlywaving human hair suitable for use in the home in the hands ofinexperienced operators, where close control of the numerous variablefactors is impossible to achieve, with a minimum risk of variation inthe effect produced upon the hair.

Another object is to provide a hair-waving composition which may bepackaged in the form of a dry powder for sale to the consumer.

Still another object is to provide a hair-waving'composition which maybe employed in the form of an aqueous solution which is free fromammonia.

Other and further objects will be apparent from the description whichfollows.

It has been discovered that alkali metal borohydrides may be employed inhair-waving compositions to attain the foregoing objects. Among thealkali metal salts which may be employed are those of potassium andsodium. Lithium borohydride which is non-ionic in character, unlike thesodium and potassium salts, is not suitable for use in the presentinvention inasmuch as this compound ignites spontaneously in air.Accordingly, the present invention is limited to those alkali metalborohydrides in which the alkali metal has an atomic weight above 20.

Of these alkali metal borohydrides, sodium borohydride and potassiumborohydride, particularly the latter, are preferred. The borohydridesare preferably applied to the hair in the form of an aqueous solution,one of the advantages of the present invention being that a considerablevariation in concentration of such an aqueous solution has relativelylittle effect upon the wave imparted to the hair by use of such asolution. It has been found that solutions varying in molarity from 0.5to 1.6 may be employed to give satisfactory'results, although aconcentration from 0.95 to 1.25 is preferred. Solutions which are evenmore dilute or more concentrated than 2,766,760 Patented Oct, 16, 1956these ranges may also be employed although the results become lessdesirable.

Aqueous alkali metal borohydride compositions within the scope of thepresent invention may vary in pH from about 8.5 to about 11.0 withoutdeleterious or damaging effects on the hair and yet be effective toproduce'a variety of curl strengths. (By curl strength is meanttightness of the wave produced, varying from very loose to very tight.)Inasmuch as the pH of the solution has relatively little effect uponcurl strength or damage within the stated range, control of pH of thesolution is not of critical importance.

However, as is well known, high pH solutions (above about 11) tend tohave an irritating effect upon the skin; and it is therefore usuallydesirable to employ solutions having a pH below this value.

The pH of an aqueous solution containing such an alkali metalborohydride varies depending upon the purity of the borohydrideemployed, and the length of time elapsing after the preparation of thesolution. Generally speaking, an aqueous solution of commercial alkalimetal borohydride above 90% in purity, when freshly prepared from solidborohydride varies considerably in pH, from about 9.7 to about 11.8. Asthe solution is allowed to stand, hydrogen gas is evolved as a result ofgradual decomposition of the borohydride and, at the same time, the pHof the solution tends to approach a pH range of about 10.5 to 10.8.

Decomposition of aqueous alkali metal borohydride solutions isrelatively slow and the rate of evolution of hydrogen is not sufiicientto constitute a fire or explosion hazard. However, it is preferred thatthe aqueous borohydride solutions of the present invention be freshlyprepared; i. e., should not be more than five or six hoursold-preferably not more than three hours old-at the time they are used.In addition, it is preferable that the dry solid borohydride be storedin sealed containers prior to dissolution in the aqueous medium in orderto avoid deterioration through contact with atmospheric moisture.

In order to obtain solutions having a pH below about 9.7, it has beenfound that special techniques are required. Merely lowering the pH byaddtion of an acid or of an acidic salt will lead to excessivedecomposition of the borohydride and vigorous eifervescence of thesolution caused by liberation of hydrogen unless the agent employed forreducing the pH is carefully chosen. It has been found that very weakacids, those having a dissociation constant less than 10 preferably from10" to 10 are suitable for reducing the pH of aqueous borohydridesolutions without excessive decomposition. Boric acid and amino acidssuch as glycine, aspartic acid, arginine, asparagine, and the like havebeen found to be particularly suitable, being employed at concentrationsranging from 0.004 M to 0.16 M so that the molar ratio of theborohydride to the boric acid or amino acid ranges from 400:1 to 3:1.

In addition, it has been found that polyhydric alcohols having more thantwo hydroxyl groups, such as glycerine and particularly sorbitol ormannitol, are quite effective in reducing the pH of such borohydridesolutions without excessive decomposition, probably through theformation of a borate complex. The polyhydric alcohols may be employedin the solution in concentrations ranging from 0.02 to 0.3 M, the molarratio of borohydride to the alcohol being from :1 to 1.7:1. if desired,the sorbitol or mannitol may be employed either alone or in mixture witheach other or in mixture with one or more ofthe above-mentioned Weakacids. For particularly low pH values, below 9.0, a combination of boricacid with calcium chloride (the latter in a concentration from 0.02 to0.2 M) may be employed.

Inasmuch as the borohydride solutions of the present invention havelittle swelling effect upon the hair, it has been found that superiorresults can be obtained by employing an agent capable of swellingthair,such as urea, methyl urea, or ethyl urea, together with the borohydride,the swelling agent being preferably employed in a concentration rangingfrom 0.5 to 3.0 M, the molar ratio between the borohydride and theswelling agent being from 3.2:1 to 0.17:1.

It has also been found that surprisingly good results can be obtained byemploying a hair-waving composition containing in the aqueous medium, inaddition to the alkali metal borohydride, a conventionalthiol ormercaptan hair-reducing agent. Accordingly, the dry borohydride powermay be added to a solution of such a conventional hair-reducing agent asa booster. Among the thiol hair-reducing agents which have been found tobe most suitable for this purpose are those containing a polar acidgroup. Particularly preferred are thio-glycolic acid and its salts,although other thiols such as cysteine hydrochloride, which containsboth a carboxyl and an amine group, may also be employed. A variety ofsuch salts may be employed, such as sodium, potassium, monoethanolamine,ethylene diamine, and other similar salts. It is preferred that ammoniumsalts such as ammonium thioglycolate be avoided since the presence ofamonium salts in the aqueous solution tends to accelerate decompositionof the borohydride with consequent effervescence of the solution.

Although the concentration of the thiol hair-reducing agent may varyover a considerable range, it has been found that the desired effect isparticularly noticeable when the thiol concentration is in the range of0.1 to 0.6 M, the molar ratio of borohydride to the thiol being from16:1 to 08:1. The molarity is defined-in terms of thiol or -SH groupspresent in the solution, one mole of a dithiol compound in a liter ofsolution being 2.0 molar with respect to the thiol groups.

The aqueous solutions of the present invention may be employed forwaving hair by conventional techniques if desired. The solution may beapplied to the hair, which may be either dry or damp, before or afterwinding upon suitable curling rods, the hair being maintained in woundor curled configuration in contact with the solution for a period oftime sufficient to split the disulfide bonds or linkages of the hairkeratin and to permit substantial plastic flow of the hair, which mayrequire from minutes to 90 minutes or more. Generally speaking, thedrier the hair at the time of application of the lotion, the tighter thecurl produced. It is usually preferable to allow the solution to remainin contact with the hair for a period of time between about 30 minutesand about 60 minutes, although one of the principal advantages of thepresent invention is that considerable variation in the time of hairtreatment has little effect upon the resulting hair wave. Following thisstep, the hair may be thoroughly rinsed with water prior to fulldevelopment of the wave in order to dilute the borohydride solution insitu on the hair to an extent sufficient to preclude any furthersubstantial chemical reaction of the borohydride upon the hair; the hairis then simply exposed to atmospheric oxygen (while still wound on thecurling rods) at ordinary room temperatures for a period of timesufficient to permit full development of the wave. Preferably the hairis allowed to stand in wound form exposed to atmospheric oxygen for aperiod of from 4 hours up to 12 hours or even longer, although times asshort as 2 hours are satisfactory. Conveniently, the hair, following therinsing step, may be allowed to dry overnight before it is unwound.

If desired, oxidation of the hair to restore the normal disulfidelinkages of the hair keratin may be accelerated by the use of aconventional neutralizing agent, i. e., oxidizing agent. When aneutralizing agent is. employed, it is preferable to permit theborohydride solution to act upon the hair for a somewhat longer periodof time, up to about 2 hours, than is the case when aerial oxidation isemployed. However, with higher concentrations of the borohydridecomposition, waving times as short as about 30 to 45 minutes may also beused, when a neutralizing agent is employed. If desired, the solution ofneutralizing agent may be applied to the hair immediately after rinsingor the rinsed hair may be allowed to remain in wound condition for aperiod of time up to about two hours after rinsing before application ofthe neutralizing agent. in employing a chemical neutralizer, the hairneed not be rinsed prior to neutralization, but is preferably merelytowel blotted, the neutralizing solution then being applied to the woundhair, preferably in two successive separate applications. Anyconventional neutralizer may be employed, such as aqueous solutions ofsodium hypochlorite, hydrogen peroxide, sodium perborate, or the like,the concentrations being those commonly employed in this well-knownstep. Following thorough application of the neutralizer to the hair andafter allowing a sufficient period of time, usually about 5 to 30minutes, for the neutralizer to act, the hair is then thoroughly soakedwith neutralizer solution to ensure complete restoration of thedisulfide bonds and elimination of any residual waving agent(borohydride) at the surface of the hair.

In addition, it has been observed that satisfactory permanent waves canbe obtained merely by applying the borohydride waving solution to thehair and allowing the hair to remain in wound or curled configuration incontact with the previously applied solution for relatively longerperiods of time; that is, three hours or longer up to overnight, withoutrinsing. Upon unwinding the hair after this period of time it may berinsed or brushed as desired.

It is contemplated that since aqueous solutions of the borohydrides areunstable as described above, the dry solid material in granular form maybe supplied directly to the consumer in measured quantities sufficientto make up a predetermined volume of waving lotion. The dry solidborohydride should of course be sealed hermetically in a suitablepackaging in order to prevent excessive decomposition or deteriorationof the borohydride by contact with the atmosphere. The other ingredientsof the waving lotion, such as boric acid or glycine, polyhydric alcohol,swelling agent and/or thiol hair-reducing agent, may be mixed with thesolid borohydride prior to preparation of the solution, or theingredients may be separately dissolved in any desired order in theaqueous medium.

In order to illustrate more clearly the nature of the present invention,but without any intention of limiting its scope, the following specificexamples are given:

Example 1 The hair, after shampooing, is parted into tresses in theconventional manner; and the tresses are individually saturated with anaqueous solution of the following composition:

Potassium borohydride 1.26 Boric acid 0.016

The Wet tresses are individually wound on conventional curlers, andfollowing the completion of the winding, they are resaturated with thewaving solution. The pH of this waving solution as applied to the hairis about 9.6. Thereafter the wound hair is left to process at roomtemperature for minutes. Following the 90-minute processing time, thewound hair is towel-blotted and thoroughly saturated with a conventionalaqueous sodium perborate solution (1%) as a neutralizer. After 5 minutesstanding, the hair is again towel-blotted and the neutralizer is pouredthrough the tresses. The hair is then rinsed and dried.

A commercially satisfactory wave of average tightness is obtained bythis procedure, the wave being substantially permanent to repeatedshampooings. V a

In order to obtain a lower pH of approximately 8.6, there was added tothe waving solution described above 0.18 M of calcium chloride. Whenthis solution was used in the process described in Example 1, the waveobtained was substantially the same, decreasing only slightly aftershampooing.

Increase of the concentration of boric acid in the solution firstdescribed to 0.064 M lowered the pH from 9.6 to 9.0, but resulted in nochange in intial wave. The curl strength of tresses treated with thissolution was sub stantially unimpaired after shampooing.

Example '2 The process described in Example 1 was carried out employingthe following aqueous waving solution:

M Potassium borohydride 1.26 Glycine 0.013

The pH of this solution as applied to the hair was 10.0. Strong curlswere produced.

Increase of the glycine concentration to 0.08 M lowered the pH to 9.1and resulted in a commercially satisfactory wave.

Example 3 The same procedure was employed as described in Example 1using the following aqueous waving solution:

M Potassium borohydride 1.0 Mannitol 0.22

The initial pH of this solution was 9.5. A satisfactory wave wasobtained. Example 4 The following aqueous waving solution was employedin the process of Example 1:

M Potassium borohydride 1.26 Mannitol a 0.22 Glycine 0.007

The initial pH of the solution was 9.6, and a satisfactory wave wasobtained.

' Example 5 6 An aqueous waving solution containing 1.6 M sodiumborohydride pH 11.0 was employed in the process'of Example 1, no otheringredients being present in the solution. The wave obtained wascommercially satisfactory. a

Substantially identical results were obtained employing a 1.05 sodiumborohydride solution.

Example 6 A hair-waving process was carried out as described in Example1 using as the waving solution the following aqueous composition:

M 'Sodium borohydride 1.05 Urea 2.0

A wave of medium curl strength was obtained.

. V Example 7 V The hair was waved as described in Example 1 withtheThis solution was employed in the process as described in Example 1except that the hair was allowed to process for only 30 minutes. Asatisfactory permanent wave was obtained.

Example 9 The hair was treated with an aqueous solution containing 1.0 Mpotassium borohydride was described in Example 1. Curls of averagetightness were obtained.

Example 10 The hair was treated as described in Example 1 with anaqueous solution containing 1.26 M potassium borohydride, initial pH10.05. A medium tight wave was obtained.

Example 11 The hair was treated as described in Example 1 with thefollowing wave solution:

Potassium borohydride 12 6 Urea 1.0

A tight wave was obtained.

Example 12 The hair was treated as described in Example 1. The

waving solution employed was an aqueous solution of the followingingredients:

M Potassium borohydride 0.76 Boric acid 0.016

The pH of the solution as applied to the hair was 9.6 and a commerciallysatisfactory wave was obtained.

Example 13 The hair was treated as described in Example 12 with thefollowing waving solution:

Potassium borohydride 1.5

Boric acid 0.016

The pH of the solution as applied to the hair was 9.6 and the waveobtained was very tight.

Example 14 Example 15 An aqueous solution containing 0.4 M thioglycolicacid was prepared and to the solution was added suflicient ethylenediamine to neutralize the acid and to bring the pH up to 9.6. Potassiumborohydride was then added to the solution to give a concentration of1.0 M potassium borohydride, and the solution was employed in theprocess described in Example 1. The wave obtained was of mediumtightness, as compared with looser waves when the borohydride wasomitted from the solution.

Example 16 An aqueous solution containing 0.4 M cysteine hydrochloridewas prepared and to it was added suflicient ethylene diamine to bringthe pH up to 10.0. There was then added potassium borohydride to give aconcentration of 1.25 M potassium borohydride, and the solution wasemployed in the process described in Example 1. A medium tight wave wasobtained.

7 Example 17 To a 0.4 M aqueous thioglycolic acid solution was addedsufficient sodium hydroxide to give a pH of 10.0. Sufi'icient sodiumborohydride was then added to the solution to give a concentration of1.05 M sodium borohydride, and the solution was employed in the processof Example 1. A loose, natural wave was obtained.

Example I 8 An aqueous solution of the following composition wasprepared: M

' Potassium borohydride 1.0 Boric acid 0.016

Example 19 The following wave solution was prepared:

Potassium borohydride 1.26 Boric acid 0.016

This waving lotion was employed in the process of EX- ample 18 exceptthat the hair was allowed to remain wound on the curling rods to dry foronly 6 hours after rinsing without being covered by a turban, butinstead being exposed to the atmosphere. Upon unwinding, the hair wasfound to have a medium tight wave.

Alternatively, in the above process, the hair after rinsing was allowedto remain wound for 60 minutes, and was then treated with a solution ofneutralizing agent as described in Example 1, rinsed and dried. The waveobtained was commercially satisfactory.

Example 20 The shampooed hair tress is dampened with an aqueous solutionhaving the following composition: M Potassium borohydride 0.8Ethylenediamine thioglycolate 0.3 Boric acid 0.016

Mannitol 0.11 Urea 1.0

pH adjusted with ethylenediamine to 9.6

The tress is then wrapped on a conventional curler, following which thewound tress is resaturated with the same composition. After processingfor 60 minutes, the wound tress is towel-blotted and neutralized in theconventional manner as noted in Example 1. A commercially satisfactorywave, stable to shampooing, was obtained.

Although we have herein described specific embodiments of our invention,we do not intend to limit ourselves solely thereto, but to include allof the obvious variations and modifications within the spirit and scopeof the appended claims.

We claim:

1. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution comprising an alkali metal borohydrideat a molarity of from 0.5 to 1.6 in which the alkali metal has an atomicweight above 20, and maintaining the hair in curled configuration incontact with said solution for a period of time sufficient to permitsubstantial plastic flow of the hair.

2. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing sodium borohydride at amolarity from 0.5 to 1.6, maintaining the hair in curled configurationin contact with said solution for a period of time sufiicient to splitthe disulfide linkages of the hair keratin and permit substantialplastic flow of the hair, and subjecting the hair in curledconfiguration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

3. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.5 to 1.6, maintaining the hair in curled configurationin contact with said solution for a period of time sufficient to splitthe disulfide linkages of the hair keratin and permit substantialplastic flow of the hair, and subjecting the hair in curledconfiguration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

4. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, maintaining the hair in curled configuration in contactwith said solution for a period of time sufficient to split thedisulfide linkages of the hair keratin and permit substantial plasticflow of the hair, diluting the solution in situ on the curled hair to anextent sufiicient to prevent further substantial chemical ac- .tion onthe hair, and maintaining the hair in curled configuration in contactwith the dilute solution for a period of time sufiicient to permit fulldevelopment of the wave and restoration of the normal disulfide linkagesof the hair through aerial oxidation.

5. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.5 to 1.6, maintaining the hair in curled configurationin contact with said solution for a period of time suflicient to splitthe disulfide linkages of the hair keratin and permit substantialplastic flow of the hair, diluting the solution in situ on the curledhair to an extent sufiicient to prevent further substantial chemicalaction on the hair, and maintaining the hair in curled configuration incontact with the dilute solution for a period of time sufiicient topermit full development of the wave and restoration of the normaldisulfide linkages of the hair through aerial oxidation.

6. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.95 to 1.25, maintaining the hair in curled config uration incontact with said solution for a period of time sufficient to split thedisulfide linkages of the hair keratin and permit substantial plasticflow of the hair, and applying to the hair an aqueous solution of anoxidizing agent to restore the normal disulfide linkages of the hair.

7. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.95 to 1.25, maintaining the hair in curled configurationin contact with said solution for a period of time sufficient to splitthe disulfide linkages of the hair keratin and permit substantialplastic flow of the hair, and applying to the hair an aqueous solutionof an oxidizing agent to restore the normal disulfide linkages of thehair.

8. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, and a weak acid having a dissociation constant lessthan 10- at a molarity from 0.004 to 0.16, maintaining the hair incurled configuration in contact with said solution for a period of timesufiicient to split the disulfide linkages of the hair keratin andpermit substantial plastic flow of the hair, and subjecting the hair in9 curled configuration to the action of an oxidizing agent to restorethe disulfide bonds of the hair keratin.

9. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the 'classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, and a member of the class consisting of boric acid andglycine at a molarity from 0.004 to 0.16, maintaining the hair in curledconfiguration in contact with said solution for a period of timesuificient to split the disulfide linkages of the hair keratin andpermit substantial plastic flow of the hair, and subjecting the hair, incurled configuration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

10. The method of permanently waving human hair which comprises applyingto-the hair an aqueous solution containing potassium borohydride at amolarity from 0.5 to 1.6, and a member of the class consisting of boricacid and glycine at a molarity from 0.004 to 0.16, maintaining the hairin curled configuration in contact withvsaid solution for a period oftime suflicient to split the disulfide linkages of the hair keratin andpermit substantial plastic flow of the hair, and subjecting the hair incurled configuration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

11. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, and a polyhydric alcohol having more than two hydroxylgroups at a molarity from 0.02 to 0.3, maintaining the hair in curledconfiguration in contact with said solution for a period of timesufficient to split the disulfide linkages of the hair keratin andpermit substantial plastic flow of the hair, and subjecting the hair incurled configuration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

12. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.95 to 1.25, and a member of the class consisting of sorbitol andmannitol at a molarity from 0.02 to 0.3, maintaining the hair in curledconfiguration in contact with said solution for a period of timesufiicient to split the disulfide linkages of the hair keratin andpermit substantial plastic flow of the hair, and subjecting the hair incurled configuration to the action of an oxidizing agent to restore thedisulfide bonds of the hair keratin.

13. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.95 to 1.25, and a member of the class consisting ofsorbitol and mannitol at a molarity from 0.02 to 0.3, maintaining thehair in curled configuration in contact with said solution for a periodof time suflicient to split the disulfide linkages of the hair keratinand permit substantial plastic flow of the hair, and subjecting the hairin curled configuration to the action of an oxidizing agent to restorethe disulfide bonds of the hair keratin.

14. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing a member of 'the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, and a swelling agent for hair selected from the classconsisting of urea, methyl urea, and ethyl urea at a molarity from 0.5to 3.0, maintaining the hair in curled configuration in contact withsaid solution for a period of time sufficient to split the disulfidelinkages of the hair keratin and permit substantial plastic flow of thehair, and subjecting the hair in curled con- 10 figuration to the actionof an oxidizing agent to restore the disulfide bonds of the hairkeratin.

15. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.95 to 1.25, and a swelling agent for hair selected fromthe class consisting of urea, methyl urea, and ethyl urea at a molarityfrom 0.5 to 3.0, maintaining the hair in curled configuration in contactwith said solution for a period of time sufficient to split thedisulfide linkages of the hair keratin and permit substantial plasticflowof the hair, and subjecting the hair in curled configuration to theaction of an oxidizing agent to restore the disulfide bonds of the hairkeratin.

16. The method of permanently waving human hair which comprises applyingto the hair an aqeous solution containing a member of the classconsisting of sodium borohydride and potassium borohydride at a molarityfrom 0.5 to 1.6, and a thiol hair reducing agent at a molarity of 0.1 to0.6, maintaining the hair in'curled configuration in contact with saidsolution for a period of time suflicient to split the disulfide linkagesof the hair keratin and permit substantial plastic flow of the hair, andsubjecting the hair in curled configuration to the action of anoxidizing agent to restore the disulfide bonds of the hair keratin.

17. The method as defined in claim 16 wherein the thiol hair reducingagent is a salt of thioglycolic acid and the pH of the solution, priorto application of the solution to the hair, has a value from 8.5 to11.0.

18. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.95 to 1.25, and a thiol hair reducing agent at amolarity of 0.1 to 0.6, maintaining the hair in curled configuration incontact with said solution for a period of time sufficient to split thedisulfide linkages of the hair keratin and permit substantial plasticflow of the hair, and subjecting the hair in curled configuration to theaction of an oxidizing agent to restore the disulfide bonds of the hairkeratin.

19. The method of permanently waving human hair which comprises applyingto the hair an aqueous solution containing potassium borohydride at amolarity from 0.95 to 1.25, a member of the class consisting of boricacid and glycine at a molarity from 0.004 to 0.16, a member of the classconsisting of sorbitol and mannitol at a molarity from 0.02 to 0.3, aswelling agent for hair selected from the class consisting of urea,methyl urea, and ethyl urea at a molarity from 0.5 to 3.0, and a thiolhair reducing agent at a molarity of 0.1 to 0.6, said solution having apH value, prior to application of the solution to the hair, from 8.5 to11.0, and maintaining the hair in curled configuration in contact withsaid solution for a period of time sufiicient to split the disulfidelinkages of the hair keratin and permit substantial plastic flow of thehair, and subjecting the hair in curled configuration to the action ofan oxidizing agent to restore the disulfide bonds of the hair keratin.

20. A composition comprising an alkali metal borohydride in which thealkali metal has an atomic weight above 20, and a weak acid having adissociation constant less than 10 the molar ratio of the borohydride tothe acid being from about 400:1 to 3:1.

21. A composition comprising a borohydride selected from the classconsisting of sodium borohydride and potassium borohydride, and a memberof the class consisting of boric acid and glycine, the molar ratio ofthe borohydride to the acid being from about 400:1 to 3:1.

22. A composition comprising potassium borohydride and a member of theclass consisting of boric acid and glycine, the molar ratio of theborohydride to the acid being from about 400:1 to 3:1.

23. A composition comprising a member of the class consisting of sodiumborohydride and potassium borohydride and a polyhydric alcohol havingmore than two 11 hydroxyl groups, the molar ratio of the borohydride tothe alcohol being from"80:1,t0 1.7:1;

24. A composition comprising-a member of the class consisting of sodiumborohydride and potassium borohydride and an alcohol selected from theclass consisting of sorbitol and mannitol, the molar ratio ofthe-borohydride to the alcohol being from 80:1 to 1.7: 1.

25. A composition comprising potassium borohydride and an alcoholselected from the class consisting of sorbitol and 'mannitol, the molarratio of the borohydride to' the alcohol being from 80:1 to 1.721.

26. A composition-comprising a member of the class consisting of sodimborohydride and potassium borohydride and a swelling agent for hairselected from the class consisting of urea, methyl urea, and ethylurea/the molar ratio of the borohydride to the swelling agent being from3.2:1 to 0.17:1.

27. A composition comprising potassium borohydride and a swelling agentfor hair selected from the class consisting of urea, methyl urea, andethyl urea, the molar ratio of the borohydride to the swelling agentbeing from 3.2:1 to 0.17:1.

28. A composition comprising a member of the class consisting of sodiumborohydride and potassium borohydride and a thiol hair reducing agent,the molar ratio of borohydride to thiol being from 16:1 to'0.8:1.

29. A composition comprising potassium borohydride and a thiol hairreducing agent, the molar ratio of borohydride to thiol being from 16:1to 0.8:1.

30. A composition comprising potassium borohydride, a member of theclass consisting of boric acid and glycine,

the molar ratio of the borohydride to the acid being from-about 400:1 to3:1, an alcohol selected from the class consisting of-sorbitol andmannitol, the molar ratio of-the borohydride to the alcohol being from:1 to 1.721, a swellingagent for hair selected from the classconsistingof' urea, methyl urea, and ethyl urea, the molar ratio-oftheborohydride to the swelling agent being -fr'om-'3.2:1-to 0.17:1, and athiol hair reducing agent, the-molar ratio of borohydride to thiol beingfrom 16:1 .to O-.8i-1.

References Cited in the file of this patent FOREIGN PATENTS AustraliaMar. 28, 1939 OTHER REFERENCES A Study of Keratin by Michaelis, in theJournal of the :American Leather Chemists Assn. for November1935,'.pages 557-558560-561562. (Copy in Div. 43).

Mellor: Modern Inorganic Chemistry (Longmans, Green-&-.Co., New York, N.Y.), 1939, pg. 658, Compounds of Boron, Boron Hydrides.

Ephraim Inorganic Chemistry (Nordeman, New York, N. Y.), 1943, pp.763-774.

Krajkeman: Reduction of Organic Compounds With Lithium AluminiumHydride. Manuf. Chem, April 1951, pp. 147-152 and 156.

Bulletin 502A, Sodium Borohydride, Metal Hydrides Inc., 12-24 CongressStreet, Beverly, Mass. 2 pages.

2. THE METHOD OF PERMANENTLY WAVING HUMAN HAIR WHICH COMPRISES APPLYINGTO THE HAIR AN AQUEOUS SOLUTION CONTAINING SODIUM BOROHYDRIDE AT AMOLARITY FROM 0.5 TO 1.6, MAINTAINING THE HAIR IN CURLED CONFIGURATIONIN CONTACT WITH SAID SOLUTION FOR A PERIOD OF TIME SUFFICIENT TO SPLITTHE DISULFIDE LINKAGES OF THE HAIR KERATIN AND PERMIT SUBSTANTIALPLASTIC FLOW OF THE HAIR, AND SUBJECTING THE HAIR IN CURLEDCONFIGURATION TO THE ACTION OF AN OXIDIZING AGENT TO RESTORE THEDISULFIDE BONDS OF THE HAIR KERATIN.